Vascular grafts of various types are known and find many applications in replacing or providing detours about native blood conduits. Example vascular grafts include synthetic grafts commonly made from expanded polytetrafluoroethylene (e-PTFE), polyethylene terephthalate (PET) or Dacron®. Another common type of vascular grafts involve autologous saphenous vein grafts. Because the patency rates of both such types of vascular grafts are relatively low, numerous studies have been undertaken to find solutions for increasing graft patency.
One solution that appears to have promise in substantially increasing graft patency is described in, for example, U.S. patent application Ser. Nos. 10/834,360, 10/987,313, and 11/797,648, which are owned by the assignee of the present application, and which are herein incorporated by reference in their entirety. Such solution involves a generally tubular scaffold externally supporting the graft segment. In particular, the tubular support is compliant to an extent that the tubular support is capable of resilient radial expansion in a manner mimicking the compliance properties of an artery. The tubular support may be formed of a knitted or woven mesh that is so formed as to exhibit the needed compliance properties.
A challenge in implementing such a tubular support is in mounting or otherwise securing the tubular support scaffold to the graft segment, and, in one embodiment, to an external surface of the vascular graft. Conventional approaches typically involve a cylindrical “straw” or support tube about which the scaffold is positioned. The first end of the vascular graft is then grasped with a clamp, such as a biopsy forceps, and is thereafter pulled through the straw lumen. As the vascular graft emerges from an opposite opening of the straw, the scaffold is removed from the straw and placed into contact with the vascular graft. Typically, a series of sutures may be required to secure the scaffold to the vascular graft.
The conventional process described above, however, has its drawbacks. For example, conventional “straws” are difficult to diametrically size commensurate with the external support device, in that the straw outer diameter must be sufficiently large to temporarily frictionally retain the external support thereat without damage to the external support, while still facilitating ease of removal of the external support therefrom in the deployment process. Moreover, the use of clamps, such as biopsy forceps, directly upon the graft can cause damage thereto.
Consequently, it is a principal object of the present invention to provide an apparatus and method for efficiently securing an external support to a vascular graft while minimizing risk of damage to such graft.
It is a further object of the present invention to provide an apparatus and method for securing a compliant external support to a vascular graft, which apparatus and method significantly simplifies the mounting process.